MOS transistors are the building blocks of many electronic devices including communication devices. One of the key operating characteristics of MOS transistors is the breakdown voltage. As the operating voltage applied to an MOS transistor increases, the transistor may eventually breakdown allowing an uncontrollable increase in current to pass through devices of a circuit. Operating above the breakdown voltage for a significant duration reduces the lifetime of the transistor. In CMOS and BiCMOS processes, for instance, the device breakdown voltage is limited by drain-to-channel junction breakdown voltage and can be improved by moving drain away from the channel. In LDMOS devices, shallow trench isolation (STI) may be employed to extend the drain, and thus to achieve a higher operating drain source voltage (Vds).